Juvenile Asian Carp as Forage for Predatory Fish in the LaGrange Reach of the Illinois River Sign up or log in to save this to your schedule and see who's attending!

The increasing abundance of silver carp (Hypophthalmichthys molotrix) and bighead carp (H. nobilis) in the Illinois River has raised questions about how native predator diets are changing due to Asian carp invasion. During the summer of 2014, a large Asian carp spawning event was observed on the Illinois River which provided an opportunity to determine how piscivorous fish (n=1527) were responding to high densities of juvenile Asian carp. Native predators were collected from the LaGrange Reach of the Illinois River (3 August through 8 November 2014) using pulsed-DC boat electrofishing. Diet contents were quantified visually then genetically, using next generation sequencing at six universal barcode loci (16s, 12s, COI, and CytB domains). Our results revealed that juvenile Asian carp were found in more than 20% (frequency of occurrence) of diets from: shortnose gar (Lepisosteus platostomus), white bass (Morone chrysops), black crappie (Pomoxis nigromaculatus), channel catfish (Ictalurus puncatus), smallmouth bass (Micropterus dolomieu), largemouth bass (M. salmoides), white crappie (P. annularis), yellow perch (Perca flavescens), flathead catfish (Pylodictis olivaris), and freshwater drum (Applodinotus grunniens). Predators analyzed throughout the sampling period foraged most heavily on juvenile Asian carp during the first month of this study, immediately after the spawning event, but switched to other prey over time. Ivlev’s electivity indicated a preference for juvenile Asian carp over native prey fish for several predator species. Additionally, smaller white bass had a greater probability of foraging on juvenile Asian carp and consumed higher counts than the larger white bass, consistent with optimum foraging theory. Results of this study indicate a possibility for a biological control of Asian carp by using native predators.